Frozen hamburgers, chicken patties, sausage patties, and other disk-like food products typically are prepared by a manufacturer on one piece of equipment and then fed into a freezer. After leaving the freezer, they are screened by a metal detector, which detects contaminated patties, and then conveyed to a stacker. The stacker forms the patties into one or more stacks, and the finished stacks are then placed in cases. Because the stacks formed by some stackers can vary in height, and because the number of stacks formed simultaneously by a stacker may be greater than the number of stacks that will fit in a row in a case, the finished stacks are often removed from the stacker and loaded into cases by hand. This manual loading step is labor-intensive, and, due to the presence of a human element, highly variable.
The problem of forming uniform stacks of patties is addressed by the novel stacking machine disclosed in the co-pending application entitled “Method and Apparatus for Stacking Discrete Planar Objects” filed concurrently herewith and assigned to the assignee hereof. The disclosure of that application is hereby incorporated by reference. However, as with many prior art devices, the subject stacker simultaneously forms more stacks than will fit in one row of a typical case. For example, in a preferred embodiment, the subject stacker receives four rows of frozen patties from a conveyor belt and simultaneously forms four stacks of patties. Cases of patties, however, can often accommodate only three stacks of patties per row, or possibly five stacks or more.
This problem could be addressed by adjusting the stacking machine to form only three stacks of patties at a time, but the reduction from four rows to three rows represents a twenty-five percent decrease in efficiency. Human packers can also address this problem by packing stacks one at a time and positioning each stack as required in a given case. However, as mentioned above, it would be desirable to fully automate the stacking and packing processes to provide greater consistency and to reduce costs.
In addition, not all cases are packed in the same manner. Some cases may hold only two rows of patties, for example, and it would be useful to have a machine that could be rapidly adjusted to convert four incoming rows of stacks into two outgoing stacks, depending on the product being packaged, or even to accommodate cases that alternate between two stacks per row and three stacks per row. Ideally, the change would be software controlled or require no more than the push of button to make. And, while reducing the number of rows is the general problem faced by the industry, under some circumstances it may be desirable to present more stacks to a packing machine than are provided at one time by a stacker—for example, if the stacker forms four rows of stacks at a time and a certain case requires six stacks in a row. Finally, the machine should be able to function under conditions where the number of incoming rows is equal to the number of outgoing rows and to do so in an efficient manner.